In this episode, I’ll discuss a titrated morphine algorithm that worked well in ED patients.
A recent randomized trial in Academic Emergency Medicine showed that IV acetaminophen use didn’t alter morphine requirements vs placebo in ED patients with acute pain. This is another in a long line of studies with IV acetaminophen that fail to show a clinically meaningful benefit.
However, the titrated morphine algorithm used in the study performed very well, with 80% of all patients reporting pain relief within 60 minutes of starting therapy.
The algorithm was a simple weight-based one that was as follows:
Initial dose of IV morphine 0.1 mg/kg
Additional IV morphine 0.05 mg/kg every 15 minutes until pain score less than 4/10
The titration of morphine was stopped if the patient reached what the authors describe as locally defined safety criteria. They did not elaborate on this criteria in the published article however according to the trial’s NCT entry the safety criteria appears to be a GCS less than 13, SpO2 less than 90% with 4 L per min O2, or uncontrolled vomiting.
Patients in the study ranged in weight from 45 to 128 kg, and there was no mention of capping the weight-based dose of morphine for obesity.
On average pain was relieved after one additional dose of morphine for a total of 0.15 mg/kg, and the average 4 hour total was about 0.2 mg/kg of morphine.
It should be noted that the patients in the study had a high level of initial acute pain with a pain score of 8/10.
Respiratory depression did occur at a rate of 7.7% in the study however none of the adverse events were rated as severe.
The authors suggest that their titrated morphine protocol be used without acetaminophen for the treatment of severe acute pain in ED patients.
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